Typewriter construction



April 5, 1 955 J. E. THOMSON 2,705,553

TYPEWRITER CONSTRUCTION Filed May 1, 1951 7 Sheets-Sheet 1 IN V EN TOR.

H Jmes Z7 9 April 5, 1955 J. E. THOMSON 2,705,553

TYPEWRITER CONSTRUCTION Filed May 1, 1951 7 Sheets-Sheet 2 J. E. THOMSON TYPEWRITER CONSTRUCTION A ril 5, 1955 Filed May 1 1951 7 Sheets-Sheet S v INVENTOR. 72/7765 774/7750,

April 5, 1955 J. E. THOMSON TYPEWRITER CONSTRUCTION 7 Sheets-Sheet 4 Filed May 1, 1951 INVENTOR. 765 Haw s-0M v/fiu J. E. THOMSON TYPEWRITER CONSTRUCTION April 5, 1955 7 Sheets-Sheet 5 Filed May 1 1951 NWN A ]N V EN TOR. .72/1/ 6 I 7 /}d/rz 1.

April 5, 1955 Filed May 1 1951 J. E. THOMSON TYPEWRITER CONSTRUCTION 7 Sheets-Sheet 6 INVENTOR. jkmes 2T 7&J/F754/7- April 5, 1955 J. E. THOMSON 2,705,553

TYPEWRITER CONSTRUCTION Filed May 1, 1951 7 Shets-Sheef 7 INVZICNTOR.

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ll l I y 222 2.52 zz 223 4 }'J B Z United States Patent Q TYPEWRITER CONSTRUCTION James E. Thomson, Munith, Mich, assignor to Western Stamping Company, Jackson, Micl1., a corporation of Michigan Application May 1, 1951, Serial No. 224,013

47 Claims. (Cl. 197-42) This invention relates to typewriter constructions, and more particularly to the structural features of a typewritmg machine which pertain to its cost of manufacture, accuracy of alignment, spacing and tracking, and durability and efiiciency of operation.

The typewriter constructions of the past have been characterized by expensive machine parts, a complexity of the coacting elements or mechanisms, and a generally high cost of manufacture, replacement and repair. It is a general object of the present invention to provide an improved typewriting machine which embodies all the essential features of standard machines but which is extremely inexpensive to manufacture, and which is constructed using a minimum number of machined parts.

It is another object to provide an improved typewriter construction of the above character, in which the parts can almost entirely be fabricated of pressed or stamped parts, and of standard Wire or rod stock. In association with this object, it is within the contemplation of this invention to provide such a typewriter which will nevertheless maintain a high degree of accuarcy in its alignment, spacing and tracking, and which will have good touch and sensitivity characteristics.

It is a further object to provide an improved typewriter of the above character, which uses a standard arrangement of letters on the keyboard and also has the standard visible type of carriage and platen.

it is another object to provide a typewriter of the above character having a novel and improved type of carriage construction. In particular, it is an object to provide a typewriter having a carriage frame which is pivoted to the main frame rather than slidably mounted thereon, thus affording a great saving in machining.

it is also an object to provide an improved carriage of the above character, which pivots in an arc substantially parallel to the type faces, thus assuring a uniform type impression in all the shift positions of the carriage.

It is another object to provide an improved typewriter of the above character in which the ribbon guide is mounted on the carriage structure rather than on the type bar guide or boot-jack, so that free pivotal movement of the carriage is allowed.

It is also an object to provide an improved carriage of the above character having a novel supporting means for the paper feed rollers movable into paper releasing position, this construction being of an extremely inexpensive and easily fabricated nature.

It is a further object to provide a typewriter of the above character, having a novel and improved type bar mechanism which is extremely inexpensive to fabricate and which maintains a high accuracy in the movement of the type bars. In particular, it is an object to provide a novel hanger for the type bars which may be constructed almost entirely of pressed or stamped parts, the type bars being engaged by the hanger in all positions to maintain accuracy of alignment.

It is a further object to provide a typewriter of the above character having novel and improved key lever construction which is especially adapted for inexpensive manufacture. In particular, it is an object to provide a typewriter having only three types of key levers, these ,levers being pivotally supported by a novel construction which allows the casing of the machine to retain the lever pivot rods in lateral position.

. It is also an object to provide a typewriter construction having an improved universal bar which is contoured to accommodate the various positions of the key lever so is to insure uniform touch and striking force for all the eys.

It is another object of this invention to provide a novel escapement means for the carriage, in which practically all of the carriage motion takes place after the type strikes the paper. In association with this object, it is within the contemplation of the invention to provide an escapement mechanism by means of which the carriage is positively held against the proper escapement stop at all times during the striking movement of the type bar, thereby taking up any tolerance or play in the parts and insuring greater accuracy.

It is another object to provide an improved carriage escapement of the double leaf type, in which the leaves are supported by a rockable cage, so that the escapement mechanism is at all times urged against the ratchet, thus assuring full engagement regardless of the end-to-end alignment of the ratchet.

It is a further object to provide an escapement mechanism of the above character, which is extremely easy to adjust in initial assembly, which prevents possible damage to the leaves during return movement of the carriage, and which permits a manual tabular movement of the carrlage.

It is also an object to provide a typewriter of the above character having a novel and improved shift mechanism of the carriage type. More specifically, it is an object to provide a shift mechanism supported on the same pivot rods as the key levers, and which has novel shift locking means which is extremely inexpensive to manufacture.

it is a further object to provide-an improved shift mechanism of the above character, having a torsion bar arrangement whereby operation of a shift key on one side of the frame will insure uniform movement of the entire carriage.

I t is another object to provide a shift mechanism of the above character, which is especially adapted for typewriters of the three-position type, in which each type face is provided with three characters, the same locking means being used for each of the shift positions.

It is also an object to provide a typewriter construction of the above character, having a ribbon mechanism of novel and improved construction. In particular, it is an object to provide a ribbon mechanism having a novel clutch arrangement for driving the ribbon spools and for reversing the ribbon manually, this construction including an easily'manipulated clutch arrangement on each spool axle.

Other object, features, and advantages of the present invention will become apparent from the subsequent description taken in conjunction with the accompanying drawings.

Figure 1 is a plan view of the improved typewriter, showing the arrangement of the keyboard and the contour of the upper portion of the casing;

Figure 2 is a cross-sectional view in elevation, taken along the line 2 -2 of Fig. l and showing the key lever mounting arrangement and other portions of the construction;

Figure 3 is a cross-sectional view taken along the line 3-3 of Fig. 2 and showing the type bar guide mounting means and the links between the key levers and type bars;

Figure 4 is a cross-sectional view along the line 44 of Fig. 2 and showing the carriage main spring and the cooperation of the escapement mechanism and rack;

Figure 5 is a cross-sectional view taken along the line 5-5 of Fig. 1 and showing the universal bar and its connection to the escapement mechanism and to the ribbon feeding mechanism;

Figure 6 is an enlarged fragmentary view of the mechanism within the area 6 of Fig. 2 showing the construction of the escapement mechanism and the carriage supporting means;

Figure 7 is a fragmentary perspective view of the escapement mechanism;

Figure 8 is a cross-sectional view taken along the line 8-8 of Fig. 4 and showing the ribbon guide operator;

Figure 9 is a cross-sectional view taken along the line 99 of Fig. 2 and showing the resilient means for holding the feed rollers in position;

Figure 10 is a detail view taken along the line 10-49 of Fig. 2 and showing the support for the ribbon guide;

Figure 11 is a fragmentary cross-sectional view taken along the line 11-11 of Fig. and showing the bell ringing mechanism;

Figure 12 is a side veiw of the machine, parts being broken away to show the space bar construction;

Figure 13 is a cross-sectional View taken along the line 13 13 of Figure 5 and showing the shift key levers; and

Figure 14 is a fragmentary view of the margin stop mechanism.

The invention is shown and described as being adapted for a typewriter fabricated almost exclusively of metal stampings and other pressed parts, wire and rod stock, and conventional springs, and for this purpose the parts will be discussed from the standpoint of their being manufactured by such methods. It will be understood however, that the novel principles of construction are equally applicable to other types of manufacture, and that in particular these principles could be utilized in more expensive constructions using machined parts and other refinements.

The typewriter comprises in general a main frame 21 secured to a base 22, a key lever mechanism generally indicated at 23, type bar mechanism 24, and a carriage assembly 25, all mounted directly or indirectly on the main frame. The entire mechanism is preferably enclosed by a sheet metal cover or housing 26 which may be prefabricated of metal stampings, and which has side walls 27 secured to side portions 28 of the main frame by screws 29.

Main frame and key levers The main frame 21 is of generally channel-shape and comprises a base portion 31 extending between the two oppositely disposed upright sections 28. Base portion 31 is preferably secured to base 22 by means of welding or other fastening means, and the length of the frame is such that it extends from a point adjacent the rear edge 32 of the base to an intermediate portion of the base. The edges of the base 22 are preferably of downturned shape, and feet 33 of soft material may be provided for supporting the base on a desk or table. The cover 26 has sloping side portions 34 alongside the keyboard, these side portions being connected by a rail 35 which may be secured to an upturned tab 36 on the base.

The supporting means for the key levers comprises a plurality of pivot rods 37, 38 and 39. As is seen best in Fig. 2, these rods are supported at their opposite ends 'by side portions 28 of the main frame, an additional support 41 being provided at an intermediate portion of these rods and resting on the base portion 31 of the frame. The pivot rods are in a substantially horizontal plane, and their ends are preferably not fixed to the frame but are merely held in apertures therein, the side walls 27 of the cover holding these rods against lateral movement when the typewriter is assembled. The typewriter keyboard is arranged in the standard manner andin particular comprises three banks of keys 42, each key preferably operating a type face having three characters. This three-level arrangement, known in the art, permits the capital letters as well as numerals and other characters to be used, while having only three banks of keys rather than the usual four banks. The key levers are of generally similar shape but are of three different proportions to accommodate the three banks of keys. In particular, key levers 43 are provided for the front row of keys, key levers 44 for the middle row, and key levers 45, for the rear row, these levers being in the usual alternate arrangement. Levers 43 are pivotally mounted on rod 37, levers 44 on rod 38, and levers 45 on rod 39. Each lever comprises an upwardly extending key portion 46, a pivot'portion 47 engaged by the pivot rod, and an actuating arm 43 for engaging the universal bar and operating the type bar.

The key levers are held in properly spaced relation by means of the slotted forward wall 49 of the shell, this wall having fingers 51 extendingdownwardly between the intermediate portions 52 of the key levers. It will be seen therefore that the key levers may be loosely mounted on their respective pivot rods without danger of unwanted lateral movement. The spacing between rods 37, 3S, and 39 is preferably half the spacing between the rows of keys, so that the lever ratios of the key levers will all be approximately equal. The height of key portions 46 of the key lever is preferably such that the rows of keys are in stepped arrangement, and project slightly above the level of sloping side portions 34 of the housing.

Type bar mechanism The type bar mechanism 24 comprises a plurality of type bars 53 which are pivotally secured to a type bar hanger generally indicated at 54, and which are actuated by the key levers through links 55. The hanger 54 is of novel construction, and preferably comprises a pair of generally rectangular plates 56 and 57. As is best seen in Figures 2 and 3, these plates are in upright position and extend laterally across the frame, their ends being spaced inwardly from the side portions 23 of the frame. Plate 56 has upper and lower flanges 53 and 59 respectively which are disposed within corresponding flanges 61 and 62 of plate 57. These flanges are joined together by welding or other means so that the plates form an integral unit.

The inner ends of the type bars are provided with circular guide portions 63 which are secured to plate 56by means of a continuous arcuate pivot wire 64 disposed Within a depression 65 in the plate 56, and secured at its opposite ends by the bolts 66. The guide portions 63 of the type bars move within guide slots 67 in plate 56 and guide slots 68 in plate 57. As seen in Fig. 4, slots 67 and 68 are in arcuate arrangement, and in particular extend radially from the printing point or contact point of the type. As the type bar 53 is swung upwardly into typing position, the circular guide portion 63 thereof will move within its corresponding slots 67 and 68. Since the width of these slots is preferably only slightly greater than the thickness of the type bar, which is of flat construction such as a stamping, the lateral movement of the type bar will be held within defined limits, and this control, plus the type bar guide adjacent the platen to be later described, assures good alignment of the characters and a minimum of piling-up and irregular spacing. The pivot wire 64 is preferably held firmly in place by a securing Wire 69 which extends across its midpoint and penetrates plates 56 and 57, the ends 71 of the wire being bent therebehind.

Since it is highly essential that the type bar mechanism be in alignment with the carriage and the remaining portions of the machine, and that the individual slots 67 and 68 themselves be in alignment, a plurality of pilot holes 72 are provided in the plates 56 and 57, as well as the mounting plate 73 to which the hanger is secured. As seen best in Figure 3, plate 73 extends upwardly from the base section 31 of the frame to which it is secured by leg 74. The bracket 73 is of substantially less height than the plates of hanger 54, and the width of the bracket is slightly greater than that of the hanger. The upper edge 75 of the bracket 73 is provided with an arcuate recess to clear the slots 63 of plate 57. In assembling the hanger and its associated type bars to the frame, the pilot holes 72 in the bracket 73 and the hanger are aligned by means of pilot pins. These pilot holes are also preferably used when fastening the plates 56 and 57 together in order to insure perfect alignment of the slots 67 and 68. As an additional feature of construction, when the plates are fabricated of pressed or stamped parts the stamping dies are preferably applied to the blanks so as to insure that the burrs produced in stamping extend in the same direction, thus insuring uniform movement of the type bars.

As stated previously, the slots 67 and 68' extend radially from the bearing point of the type. The pivot wire 64 likewise is concentric with hearing point, and as seen in Fig. 1, all the type bars are of the-same length, their outer ends 76 being bent at different angles relative to the shank of the bar so that each type face reaches the paper in an upright position. When in their retracted position, the type bars are supported by a basket pad comprising a wire 77 of arcuate shape with a rubber sheathing 78, the end of the Wire being supported by a pair of upright brackets 75 secured to the base. It will be observed that when in their retracted position the type bars are almost horizontal, and the cover may be provided with a curved upper portion 81 partially covering the type bars, this portion preferably having a recess 82 of attractive contour for increasing the visibility of the paper and for allowing the type bar to move into operative position. As is best seen in Fig. 3,the lower portion of plate 56 is provided with a plurality of vertical slots 83 within which extend the ends 84 of the key levers. The levers are thus guided for vertical movement both by the cover slots 51 and the hanger assembly.

The links 55 which transmit the movement of the key levers to the type bars consist of a plurality of irregularly shaped wires having ends 85 and 86 which are pivotally connected to the key lever and the type bar respectively. Each of the wires 55 is so disposed as to transmit the vertical movement of the key lever to movement in the plane of the particular type bar 53 to which it is connected. For example, the links at the extremities of the machine are provided with a vertical leg 87 adjacent the key lever and an inclined leg 88 above portion 87.

It will be observed that the relatively loose connection between the links 55 and the key lever and type bar will allow the momentum of the type bar to aid in striking the paper, but will in no way affect the accuracy of rnovement of the type bar, since the latter is controlled solely by the guide slots 67 and 68, and by the type bar guide to be later described. It will also be. noted that while each link 55 is of individual shape, the type bars 53 are all formed of substantially identical blanks, and that the key levers are of only three different types. This arrangement therefore contributes greatly to the reduction in cost of manufacture of the machines. The connection 86 of each link 55 to its type bar is at the juncture ofthe bar shank with the circular guide portion 63, and when the bar is in retracted position this connection is somewhat below the level of wire pivot 64. This results in an accelerating effect when the key is depressed, the resulting momentum of the type bar being effective to strike the paper sharply.

Universal bar It may be well here to describe the cooperation of the key levers 23 with the universal bar 89 which extends in the conventional manner across the actuating arms 48 of the levers. The universal bar, which operates the escapement mechanism and the ribbon feeding mechanism, is preferably a fiat bar formed into substantially C-shape, and comprises a web portion extending across the key levers and a pair of oppositely disposed arms 91 spaced inwardly from the sides of the frame. Fixedly secured to these arms 91 are a pair of rock-lug posts 92 which are preferably pivotally mounted on key lever pivot rod 38. One or more leaf springs 93 are preferably disposed above the universal bar, the end 94 of each spring engaging the upper end of the bar to urge it continually downwardly. The opposite ends 95 of the springs 93 may be supported by pivot rods 38 and 39, as shown in Fig. 2.

Means are provided on this universal bar for assuring a uniform touch and sensitivity for all the keys of the machine. For this purpose, the lower edge 96 of the universal bar is of slightly arcuate shape, convex downwardly. Since the actuating arms of the key levers are in a substantially horizontal plane as determined by their engagement with flange 59, it will be seen that the key levers at the extremity of the machine will be spaced slightly downwardly from the lower edge of the universal bar, and that this spacing will gradually decrease toward the center of the machine, the universal bar being in engagement with the central levers. It will also be observed that a plurality of notches 97 are provided in the edge 96, and that these notches are disposed above the actuating arms of each of the key levers 43 which are the levers for the front bank of keys pivoted on rod 37. The result of this construction is that when keys toward the side extremities of the machine or keys in the front bank of the machine are struck, these keys will be allowed a predetermined amount of free travel before their levers engage the universal bar and encounter the resistance of springs 93. By this time sufiicient momentum has been imparted to the type bars to substantially lessen the effort required tocounteract springs 93. 1

The importance of this construction lies in the fact that the keys toward the extremity of the machine, as well as the keys in the front bank, inherently require greater effort for their movement. In the case of the keys at the side extremities of the machine, this is because of the change in angularity or direction of movement which is produced by the keys, as a result of which the friction of the key levers and the type bars within their respective guide slots is materially increased. In the case of the front bank of the keys, the reason for the inherently greater effort-is 6 that the distance from pivot rod 37 tothe universal bar 89 is substantially greater than the distance of pivot rods 38 and 39, and this longer lever arm of course increases the resistive effect of spring 93. It will be seen there fore that this novel construction of the universal bar produces substantially uniformity in the sensitivity of the keys as well as the striking forces of the type bars and that this result is produced by an extremely inexpensive expendient.

Type bar guide The bootjack or type bar guide 98 is fixedly secured to the plate 57 of the hanger 54 and extends upwardly therefrom. As is best seen in Figure 3, the guide 98 is centrally located with respect to the machine and the upper edge thereof is provided with a pair of oppositely disposed guide tabs 99 having rounded edges 101 with a clearance space 102 therebetween slightly greater than the thickness of the type bars. As seen best in Figure 2, the guide 98 is inclined forwardly from its supporting portion so that the tabs 99 are adapted to receive the type bar therebetween and to thus insure consistent alignment and tracking of the type. It will .be observed that the guide 98 does not support in any positive manner the ribbon guide 103 which, as will later be seen, is mounted on the carriage mechanism. The ribbon guide, however, is held against forward movement away from the platen since it is normally disposed between the platen and the guides 98. It will also be seen that the type bar guide in no way interferes with the visibility of the typing, and affords a locking device for the type when at the printing point to prevent any undesired motion of the bars.

Carriage mechanism As seen best in Fig. 13, the carriage mechanism 25 is pivotally secured to the main frame of the machine by means of a pair of upright posts 104 extending upwardly from the forward end of guide portions 28 of the main frame. The upper ends of these posts carry pivots 105 to which are secured the side members 106 of the carriage frame, the latter preferably comprising flat plates in sub stantially the same plane as portions 28. When in their lower position, the lower edges of the side members are supported by the upper edges 168 of the portions 28, and it will be noted that the pivots 165 are disposed a substantial distance above edges 108 and at the extreme forward end of the base. The rear portions of carriage frame members 186 have upward extensions 109, the upper ends of these extensions having inclined tabs 111 to which are secured the carriage rail 112. The carriage rail is inclined forwardly and comprises a flat intermediate web portion and a pair of oppositely disposed ball bearing races 113 and 114 extending laterally from the web portion. It will be noted that the preferred construction of the race portions as V-shaped troughs bent from their flange sections is such that the carriage rail may be readily formed from a sheet metal stamping.

The carriage 115 is slidably disposed on the carriage rail and likewise comprises a web portion and a pair of oppositely disposed trough-like ball bearing race portions 116 and 117 cooperating with the races 113 and 114 respectively of the carriage rail 112. Disposed between the rail and carriage is a ball bearing cage 118 having a flat web portion and lateral retainer flanges 119 and 121 for retaining the ball bearings 122. The ball bearings, of which there are at least two within each pair of races, are preferably tightly engaged by the races to prevent lateral play of the carriage on the rail. For this purpose, the spring'like qualities of the races, which are formed as lateral flanges on their respective elements may be utilized.

It will be observed that the length of the carriage rail is somewhat greater than the width of the main frame, while the length of the carriage itself is substantially the same as the width of the frame. The length of the cage 118 is somewhat less than the length of carriage 115, and since during the movement of the carriage the cage moves at half the rate of speed of the carriage, it will be observed, as for example, in Fig. 14, that the cage will project outwardly from the space between the carriage and rail at the extremities of carriage movement. This action is of importance, as will be seen later, in the margin stop mechanism of the machine.

Platert and feed mechanism The ends of the carriage are provided with a pair of platen shaft bearings comprising upstanding ears 123, these cars supporting the platen shaft 124. The platen which is supported by this shaft preferably comprises a rubber-like or other resilient sheathing 125 and a core 12-6 which may be constructed of wood or similar material. The ends of the platen are spaced inwardly from bearings 123, and a platen feed ratchet 127 is secured to one end of the platen, this ratchet being of circular shape and having axially extending teeth. The opposite end of the platen shaft is provided with a compression coil spring 128 between the adjacent bearing 123 and the platen core 126', the spring continuously urging the ratchet teeth against a ratchet pawl 129 which may comprise a projection inwardly pressed from the adjacent bearing 123. The ends of the platen shaft project outwardly from the bearings 123, and are provided with a pairof oppositely disposed platen knobs 131. 139011 rotation of either of these knobs the ratchet teeth 127 will ride over the pawl 129, and upon release of the knob the spring 123 will positively hold the ratchet teeth against the pawl, thereby providing accurate feed movemcnt for the platen.

. Feed rollers The carriage is further provided with a plurality of feed rollers 132 which are resiliently held against the platen to positively grip the paper therebetween. The feed rollers 132 are supported by a feed roller frame 133 which preferably comprises an elongated sheet metal stamping of arcuate cross-sectional shape adjacent the platen, as best seenin Fig. 2, the rear portion of the feed roller "rarne extending upwardly and rearwardly away from the platen. The arcuate portion of the feed roller frame is concentric with the lower portion of the platen and is slightly spaced therefrom. The frame is provided with a plurality of cars 134 which support the feed roller shafts 135, the frame adiacent the feed rollers being apertured to permit the rollers to engage the platen.

The opposite ends of the feed roller frames are provided with a pair of extensions 136 which are pivotally secured at 137 to the platen shaft bearings 123. The location of the pivots 137 is such that rocking movement ofv the feed roller frame will cause the feed rollers to separate from the platen. The feed roller frame is normally urged into its platen-engaging position by means of a wire spring 138, best seen in Fig. 9. The intermediate portion 139 of this wire spring is secured to the web of carriage 115 by means of loops 14-1, and the ends 142 of the springs are looped and engage an interned flange 143 at the upper edge of the roller frame. The spring will therefore urge the frame 133 in a clockwise direction around'its pivot point 137, as seen in Fig. 2. thus holding the feed rollers 132 firmly in engagement With the platen. When it is desired to relieve the pressure of the feed rollers on the platen, it is merely necessary to manually press the flange 143 downwardly, thus compressing spring 133. it will be noted that the wire spring will distribute its force in such fashion as to apply an even pressure along both rollers, so that the paper will feed evenly.

The flange 143 may also hold a paper bail 144, this hail being swingable over the platen to hold the paper thereon.

as seen in Fig. 3, these portions, which are of arcuatc shape corresponding to the platen, will serve tohold the margins of the paper against the platen.

Escapcmenz mechanism The escnpement mechanism is of the rack type and its general arrangement is shown best in Figs. 4 and 6. The carriage 115 is provided with an elongated rack 145 which extends along the ball bearing race 116 and has downwardly facing teeth 146. These teeth are of saw-tooth shape and are arranged so that they ride over the escapement pawls duirng return movement of the carriage. The carriage is urged in its spacing direction by a main spring 147 having one end 148 secured to the left side (with respect to the operator) of the carriage frame 106, the opposite end 1451 of the spring holding a pulley 151. The carriage draw band,152 engages this pulley, one end 153 of the draw bandbeing it will be observed that since the side portions 136 of the feed roller frame 133 are of substantial width,

mediateportion .178 of the actuating bar.

.8 secured to the right side of the carriage frame 106, and. the other end 154 to the right underside of the carriage. The arrangement is therefore such that the carriage is constantly urged from right to left with respect to the operator (or from left to right, as seen in Fig. 4), the carriage being releasably held against such movement by the escaperncnt mechanism.

The escapement itself is shown best in Figs. 4, 6 and 14 and is generally of the double leaf type. The escape ment is supported by a cage 155 which is pivotally secured to the underside of the carriage rail web by a pin 156 extending between a pair of ears 157 and 158. The cage 155 is of generally channel-shape, and the downwardly extendinglegs 159 thereof support at their outer ends a pawl pivot pin 161 for supporting the escapement pawls 162 and 163. in particular, pawl 162. which is in the form of a substantially rigid elongated leaf, is fixedly secured to the pin 161 at an intermediate portion thereof and extends upwardly from said pin through an elongated clearance aperture 164 in the web portion of the cage 155. Pawl 163 is a resilient leaf spring which is adjacent pawl 162, and the lower end thereof is secured to pawl 162 by a rivet or other fastener 165. The spring pawl 163 extends upwardly alongside the pawl 162, and the inherent spring tension inthc spring pawl normally urges it into a bowed position away from pawl 162, as shown in Fig. 14 and by the dot-dash lines 166 in Fig. 4. The spring 163 is of such length that it extends upwardly almost to the upper edge of pawl 162, and as shown best in Fig. 1 the spring has a clearance aperture 167 in the vicinity of pin 161, so that the spring is permitted to move axially with respect to this shaft. The width of leaf spring 163 is somewhat less than that of pawl 162, and-the upper edge of the leaf spring is provided with a notch 168 at its forward end. The pawl 162 is likewise provided with a notch 169, this notch however being out of alignment with notch 168, since it is rearwardly spaced therefrom, the upper edge of spring 163 therefore overlapping the notch 169. Means are provided for constantly urging cage 155 upwardly so that the upper edges of paw]. 162 and spring leaf 163 engage the rack teeth 146 of the carriage. This means comprises a coil spring 171 which is secured at its upper end indirectly to the frame. In particular, the ear 158 is of elongated shape and has pivoted to its outer end a ribbon guide actuating lever 172 which, as will be later seen, acts to lift the ribbon guide 163 during the typing stroke. The upper end of the spring is secured to an ear 173 on this ribbon guide actuating lever. The lower end of the spring is secured to an actuating bar 174 which is of general U-shape, and is moved by the universal bar rocking posts 92. For this purpose, the arms 175 ofbar 172 are pivotally connected at their ends 176 to the upper ends of posts 92, and these arms extend past the hanger mechanism 54 to the rear of the machine. The lower end of pawl 162 is provided with a recess 177 Within which is disposed the bent-out inter- In effect, therefore, the upper end of spring 171 is fixed to the carriage frame, while the lower end thereof constantly urges bar 174upwardlyinto engagement with pawl 162. 'Sin'ce this pawl .is secured to the pin 161 which is held by the cage 155, the cage is constantlyurged upwardly or in a clockwisedirection' as seen in Fig. 6, around its pivot pin 156.

ln operation, the actuating bar 174 is rocked forwardly and then rearwardly with each stroke of the keys, or between the solid and dot-dash positions in Fig. 6. This movement will cause counterclockwise and then clockwise rocking of the pawl 162 and spring 163 about the pin 16].. Before this movement begins, the mechanism is in its lockingposition in which the. upper edges of the pawl and spring are in locking engagement with a particular-tooth 146 of the rack. In particular, the notch 169 of pawl 162 will be in alignmentwith the rack teeth, but since the upper edge of spring 163 is engaged by the tooth, this spring will be held against the side of the pawl 162 by spring 147. The carriage will thus be held firmly in position before the start of the stroke, since all lost motion will be taken up in the escapement. When the pawl and spring are rocked counterclockwise as seen in Fig. 6 toward their holding position, the upper edge of the spring 163 will slide across the face of tooth 146 until its notch 168 comes into alignment with this tooth, Since by this time the, notch 16,)

of pawl 162 has been brought out of alignment'with the tooth, the tooth will fall onto the upper edge of the pawl 162 and will be held thereby, since this pawl is of suflicient rigidity to resist spring 147. The spring 163, since it is released from engagement with the rack is now free to move into its dot-dash position 166, as shown in Fig. 4. The limit of this position will be the side edge of clearance aperture 164, and this aperture is so constructed as to permit the spring 163 to move a distance equal to the pitch of one rack tooth.

Upon releasing movement of the key, the actuating bar will be moved to the left as shown in Fig. 6, rocking the pawl and spring clockwise, still in their spaced condition. The upper edge of the pawl 162 will ride across the tooth until the notch 169 thereof comes into alignment with the tooth. The rack is then free to move abruptly in a spacing direction under the urging of spring 147, the rack tooth 146 passing through the notch 169. -At the same time, the next adjacent rack tooth engages the upper edge of leaf spring 163, since the notch 168 of this leaf spring is brought out of alignment with the rack before notch 169 is brought into such alignment. The resultant motion of the carriage will bring leaf spring 163 alongside pawl 162, and the parts will then be back-in their original locking position.

It will be observed that there is no motion of the carriage, other than an amount equal to the thickness of spring 163, during the original counterclockwise movement of the parts, and that the spacing motion occurs after the parts have left their holding position, that is, after the type has struck the paper. This is important since it assures a positive positioning of the carriage during the striking movement of the type, and the carriage movement only occurs after the impression has been made. it will also be observed that since the cage 155 is constantly urged upwardly, the pawls will always fully engage the rack teeth 146. It is therefore obvious that even though there be end-to-end misalignment of the rack, the escapement will operate with full efficiency even at the extremities of the rack, the cage automatically adjusting the pawls to rack height. This is important since the rack may be formed from a stamping process which of necessity has larger tolerances than a rack having machined teeth.

The return movement of the carriage is accomplished by merely pushing the carriage in its return direction while the escapement is in its locking condition, the inclined surfaces of teeth 146 riding over the upper edge of leaf spring 163. It will be observed that since the movement of this leaf spring is limited by the side edge of aperture 164, there is no danger of damaging this spring, and the cage will reciprocate up and down as the rack teeth ride over the spring.

A tabular control is also preferably provided on the escapement, and this control comprises an extension 179 on the cage 155. Manual engagement of this extension to push the cage downwardly will free both pawls from the rack, allowing the spring 147 to move the carriage toward the end of the line, or to the right as seen in Fig. 4. Upon releasing tab 179, the spring 171 will immediately urge the cage upwardly, engaging the pawls with the rack.

Ribbon guide mechanism The ribbon 181 is guided by a conventional ribbon guide 103, best seen in Fig. 3, which has the usual plurality of upwardly extending fingers 182 holding the ribbon in fiat taut position adjacent the platen. The lower or supporting end 183 of the ribbon guide is slidably mounted on a U-shaped ribbon guide supporting bracket 184, by means of oppositely disposed gripping tabs 185 on the ribbon guide which engage bracket 184 as shown in Fig. 10. The rear portion 186 of this bracket is secured to the underside of the carriage rail 112, the bracket extending under the ball bearing races 114 and 117 and in front of the carriage. The supporting end of the bracket is forwardly inclined so that the ribbon guide moves in an inclined direction tangent to the platen. The bracket 184 may be formed integrally with the ears 157 and 158 which support the escapement cage 155, the ears extending from portion 186 of the bracket.

It is important to observe that the ribbon guide 103 is in no way secured to the type bar guide or bootjack 98, but is entirely supported by the carriage frame. There is thus no restriction to the pivoting movement of the carriage frame, since when this pivoting movement takes place the ribbon guide. will be swung away from its position adjacent the bootjack.

Means are provided for lifting the ribbon guide upon actuation of the keys to move the ribbon into alignment with the type face. This means comprises the ribbon guide lifting lever 172 which, as previously described, is pivotally secured to the elongated car 158 supporting cage 155. As is best seen in Figs. 6 and 8, this lever is of generally bell crank shape and comprises a ribbon guide engaging arm 187 which projects into an elongated slot 188 at the lower end of the ribbon guide supporting portion 184. The lever is also provided with a downwardly extending arm 189 which is disposed immediately rearwardly of the actuating bar 174. The intermediate portion of lever 172 is provided with a laterally extending tab 191 which is in the path of movement of spring 171 when the latter is actuated by the forward movement. of actuating bar 174. As will be seen in Fig. 8, this rocking movement of spring 171 will therefore bring itinto engagement with tab 191, rocking the ribbon guide lifting lever counterclockwise into its dotdash position 192.

In operation, when the universal bar is moved, the forward movement of the actuating bar 174 will rock lever 172 counterclockwise, causing the ribbon guide 103 to be lifted into operative position. Upon releasing movement of the universal bar, the rearward movement of the actuv ating bar will cause the spring pressure on tab 191 to be released and the ribbon guide will drop, this dropping or retracting movement being aided by the engagement of actuating bar 174 with retracting arm 189 of the lever 172.

Means are provided for limiting the upward movement of the ribbon guide, and this means preferably comprises an upwardly extending stop 193 on lever arm 187. As is best-seen in Fig. 6, the upward movement of the lever arm will cause abutment of stop 193 with the underside of bracket 84, thus preventing further movement of the lever. It will be observed that this lifting movement is the same no matter what' shift position is assumed by the carriage. This is because shifting of the carriage will simultaneously shift the complete ribbon guide mechanism which is mounted entirely on the carriage, so that it is only necessary to lift the ribbon guide the same amount in each shift position when striking the keys. This construction theretofore permits a great reduction in cost of manufacture, since it is not necessary to provide variable lifting movement of the ribbon guide for different shift positions on the carriage.

Ribbon spool mechanism The ribbon spool mechanism preferably comprises a pair of oppositely disposed spools 1.94 which are operated by escapement and clutch mechanisms of substantially identi cal construction, only one of which need be described. The spools are rotatably supported on vertical shafts 195, these shafts being in turn supported by brackets 196 which are secured inwardly of the carriage frame sections 106. Each bracket is of substantial C-shape and has upper and lower legs 197 and 198 respectively for supporting shaft 195, a retainer pin 199 on the shaft holding it in position. The spool is held in spaced relation above the arm 197 by a fixed disc 200, a friction washer 201 being disposed between disc 200 and the underside of the spool. The upper end of the shaft is provided with a clutch comprising a generally rectangular snap washer or plate 202 of springlike material which is preferably fixed to the shaft and is capable of overcenter movement between a downwardly cupped position engaging the usual irregularities on the spool surface, and an upwardly cupped position shown by the dot-dash lines in Fig. 2, disengaging the spool. By manually lifting the spool the clutch plate 202 can be moved from its engaging to its disengaging position, and by pressing on the plate it can be downwardly cupped. Since the spools are freely mounted on the shafts, it will be seen that by having one plate 202 engaged and the other disengaged, one spool will be positively driven by the rotating shaft to wind the ribbon while the other spool freely rotates on its shaft to unwind. The clutch plates are preferably provided with recesses 203 for engaging the usual projections on the surface of the spool, thereby aiding their gripping action.

The preferred driving mechanism for the. spool shafts positely disposed stops ether end of cage 118.

the other two stops 214 the shaft immediately above the ratchet. The .outer end of bracket 205 rockably supports a drive pawl 206 by a pivot 207, and this pawl has a tooth 208 engageable with the ratchet teeth. A clearance aperture 209 is provided in the bracket 205 to permit the tooth 208 to extend therethrough. The opposite end of pawl 206 is con.- nected by a link 211 to the universal bar rocking post 92, as seen in Fig. 2, the end connections of link 211 being preferably of a loose pivoted nature.

In operation, the arrangement is such that upon clockwise movement of the post 92, as seen in Fig. 2, the link 211 will rock pawl 206 clockwise as seen in Fig. 5. This movement will disengage the tooth 208 from ratchet 204, and will simultaneously pull the bracket 205 clockwise about shaft 195. A coil spring 212 may be provided on shaft 195 to hold the bracket 205 in position. The linkage arrangement is preferably such that the rocking movement of bracket 205 will bring tooth 208 into alignment with the next succeeding tooth on the ratchet 204. Return movement of the universal bar will cause rocking posts 92 to move counterclockwise in Fig. 2, the movement being positively carried out by leaf springs 93, as previously described. This will first cause pawl 206 to rock counterclockwise in Fig. about its pivot 207, thus engaging tooth 208 with the ratchet. Continued movement of link 211 will cause ratchet 204 to rotate counterclockwise, thus feeding the ribbon if the clutch plate 202 engages the ribbon spool. If the clutch does not engage the spool, the rotation of shaft 195 will result in no spool movement. As is seen in Pig. 5, the arrangement is such that the ribbon driving mechanisms rotate the shafts 195 in opposite directions, the shaft on the left side of the drawing being driven counterclockwise and the shaft on the right side clockwise. To reverse the ribbon, therefore, it is merely necessary to reverse the engagement of clutch plates 202.

It will be observed that the various elements which constitute the spool feed mechanism are such that they may be easily fabricated of sheet-metal stock and wire rod. For example, the bracket 205 may be a flat sheetrnetal stamping, with the clearance aperture 209 being of elongated shape to accommodate the bent-down end flange 208 which constitutes the tooth of pawl 206.

Margin stop mechanism Means are provided for limiting the carriage movement at either end of its stroke, this mechanism being shown best in Figs. 12 and 14. As stated previously, the opposite ends of ball bearing cage 118 are adapted to project from the space between the carriage and carriage rail at either end of the stroke, because of its motion at half the speed of the carriage. This projecting position is shown in Fig. 14, and it will be seen from this figure that the side edge 213 of the cage is adapted to engage one of a a pair of oppositely disposed stops 214 which are bent laterally from the rack portion of the carriage 115. This engagement will prevent further movement of the carriage with respect to the cage in the same direction. The carriage rail 112is likewise provided with a pair of op- 215, and it will be understood that the. stop 215 at the end of the carriage rail opposite the step 214 shown in Fig. 14 will simultaneously engage the The simultaneous engagement the double dot-dash lines 217 in this figure. The reason for the double shift is so that one shift position may be used for capital letters and the second shift position used for numerals and other characters. Although the illustrated embodiment is of the double shift type, it will be understood that the principles of the shift construction are equally applicable to typewriters having only a single shift position.

The shifting mechanism comprises a pair of intermediate shift key levers 218 and 219 on opposite sides of the machine passing through clearance apertures 220 in the cover, and being pivotally mounted on key lever pivot rod 39 by means of an elongated slot 221., These key levers are of substantially identical construction, and each comprises a key arm 222 and an actuating arm 223 extending rearwardly from the pivot extension 224. The arms 223 are each adapted to underlie a pin 225 which projects laterally from a carriage actuating link 226, the upper ends of links 226 being pivotally secured to. the carriage at 227. The two pins 225 are preferably formed as the turned-in end portions of a torsion bar 228 which extends across the machine and is supported for rocking movement by a pair of brackets 229 secured to the frame of the machine. The upright frame plate 73 may be provided with a pair of posts 231 which are disposed outwardly of the lever arms 223 for guiding their movement. The ends of the actuating arms 223 have locking toes 232 which extend rearwardly therefrom above the axis of the actuating arms and are engageable with looking brackets 233. These brackets extend upwardly from the frame base and are provided with laterally extending stop flanges 234 for limiting the upward movement of the lever arms by engagement of the locking toes therewith. The brackets are further provided with rectangular locking apertures 235 as seen in Fig. 4 for receiving the locking toe 232 of either key lever when it is slid rearwardly on pivot rod 39 after being depressed.

One side of the machine, the right side in the illustrated embodiment, is further provided with an upper shift key lever 236, as shown in Fig. 12. This key lever, the key arm of which may be spaced rearwardly from the arm 222 of its adjacent intermediate shift key lever, is rockably mounted on a pin 237 projected inwardly from the frame portion 28, by means of an elongated aperture 238. The actuating arm of upper shift key lever 236 is provided with a locking toe 239 which differs from the locking toes 232 of the intermediate shift key levers in that it is in line with the axis of the actuating arm, rather than spaced upwardly therefrom. The actuating arm of the upper shift key lever 236, like that of the intermediate shift key levers, underlies the pin 225 at one end of torsion bar 228. It will be understood that although two intermediate shift key levers and only one upper shift key lever is shown, other arrangements could be followed, since the numbers of levers is not critical.

In operation, the shift key leverswill normally be' in their horizontal position as shown by the full lines of Fig. 13, in which figure their major portions overlap. When it is desired to lift the carriage into its intermediate shift position as shown by the dot-dash lines 216, either intermediate shift key is depressed, thus moving link 226 through pin 225 and lifting the carriage of the opposite ends of the cage by stop members on the y carriage and carriage rail respectively will prevent further movement of the carriage with respect to the rail. Likewise, when the carriage is moved in the opposite directioh, the ends of cage 113 will project from the space between the carriage and rail, and will be engaged by ping mechanism is thus provided which will insure accurate margins on the paper, and which utilizes the inh'ercnt functions of the carriage assembly for this purpose. it 'will be understood that although in the illustrated embodiment the cage is shown as projecting from the space between the carriage and rail before it is engaged by the stops, this arrangement is not necessary, as long as the cage is simultaneously engaged by stops on thecarriage and rail.

Shift mechanism fl ig. 13, and an upper position shown by the double dotdash lines 216 of Fig. 13, and an upper position shown by and 215. An inexpensive stop- I 106 about its pivot. This lifting movementv will continue until the upper edge of tee 232 abuts the underside of stop 234 on bracket 233. The arrangement issuch that when this abutment takes place, the carriage will be in position so that striking of any key will cause the capital letter of that key, which is formed at the central portion of the type face, to strike he ribbon. I will be observed that the ribbon will be carried upwardly with the carriage,

as stated previously, so that only the normal lifting move- "ment of the ribbon need be applied. If it is desired to lock the carriage inthe intermediate shift position, the shift key is manually slid rearwardly (away from the operator) so that the elongated slot 221 rides across pivot rod 39. When this movement takes place, the locking toe 232 will enter the aperture 235 in bracket 233,and upon release of the shift keythe key will be held in its upper position by the engagement of projection 232 with the lower edge of the aperture. This lower edge is of such height as to hold the carriage accurately in its intermediate shift position. When it is desired to release the carriage, the key 222 is retracted toward the front of the machine, upon which movement'projection 232 will greases drop away from aperture 235 due to the weight of the carriage.

When it is desired to shift the carriage into its upper shift position, the upper shift key 236 is depressed, thus lifting the carriage into the double dot-dash line position 217. This extra movement will take place because of the greater distance which must be traversed before stop projection 239 engages the underside of stop 234. If it is desired to lock the carriage in its upper shift position, the key 236 is slid rearwardly on its pin 237, thus engaging the underside of projection 239 with the lower edge of aperture 235. Releasing of the carriage from its upper shift position is accomplished in the same manner as its release from the intermediate shift position, that is, by retracting the upper shift key 236. a

The action of the torsion bar during this operation will be to insure equal movement of both sides of the carriage. It will be seen that when either pin 225 of the torsion bar is lifted, the subsequent torsional force in the bar will cause equal movement of its opposite pin 225, and since both of these pins are linked to the carriage by members 226, the opposite ends of the carriagewill swing equally.

Means are preferably provided for lessening the force required for operating the shift keys, and this means may comprise a shift balance spring 241 secured atitsupper end 242 to the stationary hanger assembly plate 57, and at its lower end 243 to the torsion bar pin 225 at one side of the machine. This spring, while being too weak to lift the carriage by itself will lessen the manual force required to lift the carriage, and yet will allow it to drop instantly when released.

It is well to observe that since the brackets 196 which support the ribbon spool mechanisms are secured to the carriage frame, these mechanisms will move directly with the carriage, so that no additional stress will be put on the ribbon 181 when the carriage is shifted. It is also important to note that because of the position of the carriage pivots, the shifting movement of the carriage is such that no matter What the shift position of the carriage may be, a full and clear impression will be received from the type. In this connection, it should be noted that the pivot axis of the carriage mechanism is relatively high and well forward of the printing point, so that the shift movement Will have a relatively flat curvature. Moreover, the tangent point of the type face on the platen will be in the same peripheral position on the platen for all the shift positions, so that the lower case letters, caps, numerals and other characters will all be in exact alignment in every line.

Space bar mechanism Means are provided for spacing the carriage, and this means preferably comprises a space bar 244 in the conventional position at the front end of the machine. The bar moves two oppositely disposed spacing levers 245 which are pivotally mounted on pivot rod 37, as seen in Fig. 2. The pivot extensions 246 of these levers have lateral bends 247 therein, and the actuating arms 248 of the levers extend at a slightly downwardly inclined angle rearwardly of the pivot extensions. In the illustrated embodiment, these actuating arms 248 are provided with lateral abutment elements 249 in the form of bends in the arms, and these abutments are adapted to underlie the side portions 91 of the universal bar 89. A wire spring 251 is secured on one end to pivot rod 39 and extends over pivot rods 37 and 38, the opposite end of the wire spring engaging the underside of one of the space bar levers 245 forwardly of its pivot point, as shown in Fig. 12. Spring 251 therefore normally urges the spacing levers counterclockwise as shown in Fig. 2, disengaging abutments 249 from the universal bar.

In operation, when the space bar is depressed, the actuating arms 248 will be lifted so that abutments 249 rock the universal bar clockwise. The result of this movement will be to actuate the carriage escapement mechanism and the ribbon feeding mechanism so that the carriage will be spaced one unit. It will be observed that the movement of the space bar mechanism in no way interferes with the movement or position of the shift keys, and that this mechanism will operate no matter what the shift position of the carriage. It will also be noted that the movement of the space bar is free for a substantial distance before it engages the universal bar,

14 so" that substantial momentum may be built up in the space bar before it encounters the resistance of springs 93. The space bar is thus extremely easy tooperate and will require little effort.

Signal mechanism Means are provided for warning the operator when the end of the line isabout to be reached. This means preferably comprises a bell 252 secured by a pinto the back wall 253 of the shell. This bell is adapted to be struck by a striking lever 254 pivotally secured to the wall 253 by pin 255. The lower end of lever 254 is yieldably held by the upper end 256 of a'spring 257, the lower end 258 of which is secured to an eye 259 on the base plate 22. The upper end 261 of lever 254 projects upwardly and into the path of a tripping member 262 secured to the right end of rack 145. When the end of the line is approached, the inwardly extendingtoe 263 of tripping member 262 will engage the upper end 261 of lever 254, and will subsequently-ride past this lever, at which point the tensioned spring 257 will snap the lever back against bell 251, warning the operator that the end of the line is about to be reached. i

General operation In describing the general operation of the niachine',fit will be assumed that the detailed functions of the elements will be understood from the previous description, the main purpose of this section being to show the correlation and coaction of the various mechanisms. Starting from an initial condition in which the carriage is in its lower shift position and the paper has not been placed in the carriage, the paper ball will be swung to its rearward position as shown by the dot-dash lines in Fig. 2. The paper is then fed between the back portion of the feed roller frame 133 and the rear of the platen-125, and the platen knob rotated to feed the paper between the feed rollers 132 and the platen. During this movement the arcuate-shaped feed roller frame will guide the paper around the platen. After the paper is fed upwardly from the forward end of the platen, the paper bail is swung forwardly to hold the paper down. If it is desired to readjust the paper, the upper edge 143 of the feed roller frame 133 is pressed manually downwardly against the action of spring 138, to momentarily relieve the pressure on the paper.

bearing cage 118 to prevent further movement of the carriage. To indent from the margin, the space bar 244 is depressed several times, rocking the universal bar assembly to actuate the carriage escapement.

If it is desired to start the copy with a capital letter, one of the intermediate shift keys 222 is depressed, pivoting the carriage frame 106 about its pivot to the dotdash position 216 of Fig. 13. When a character key is struck, the actuating arm 48 of the corresponding key lever will move upwardly, moving its corresponding link 55 which will pivot the connected type bar 53 from its rest position against basket pad 78 to its striking position within the type bar guide 98. Simultaneously with this action, the actuating arm 48 of the key lever will rock the universal bar clockwise as seen in Fig. 2, thusrocking the posts 92 clockwise and pulling the actuating bar 174 to the right. The movement of actuating bar 174 will rock the escapement mechanism from its locking position into its holding position to prepare the carriage for advancing movement. At the same time, the actuating bar 174 will rock the ribbon guide lifting lever 172 counterclockwise as shown in Fig. 2, lifting the ribbon guide 184. The movement of posts 92 will also pull links 211 to the right in Fig. 2, actuating the ribbon spool feed mechanisms. Releasing the key will permit the type bar 53 to be moved back into rest position under the influence of springs 93 which will force the universal bar 98 downwardly upon the key levers. This downward movement of the universal bar will also move actuating bar 174 to the left in Fig. 2, allowing the escapement A mechanism to advance the carriage one space, and moving links 211 to advance the ribbon onto the spool held by clutch plate 202. This movement will also result in clockwise motion of the ribbon guide lifting lever 172 allowing the ribbon guide to drop.

If it is desired to hold the carriage in the intermediate or upper shift position, the appropriate shift key will be depressed and then pushed rearwardly, engaging its locking toe with the corresponding locking bracket 233. When the end of the line is reached, as announced beforehand by lever 254 striking bell 251, the margin stops 214 and 215 will come into play to prevent any further movement of the carriage, and the carriage may then be returned to its original position. At the same time the platen may be fed to the next line by rotation of a hand knob 131, this rotation causing ratchet 127 to ride over pawl 129 against the action of spring 128.

While it will be apparent that the preferred embodiment of the invention herein disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

l. A typewriter comprising a base, a plurality of key levers mounted on said base, a plurality of type bars pivotally supported adjacent said key levers and operatively connected thereto, said type bars having type faces movable between a lower and forward rest position and an upper and rearward striking position, a platen for holding paper in position to receive a type impression from said type faces, a carriage assembly for supporting said platen, and a pivotal support on said base for said carriage assembly, the assembly being connected for pivotal movement as a unit about the support, said support being at a level substantially above the rest position of all of said type faces and a substantial distance for wardly of said striking position, whereby the movement of said platen is approximately parallel to said type faces when in their striking position. 2. In a typewriter construction, a main frame having a base portion-and two oppositely disposed flange portions, aplurality of key levers, pivotal supporting means for said keylevers, said supporting means comprising a plurality of rods extending between said frame flange portions, and a cover for said typewriter, said-cover having portions overlying said flange portions, whereby said rods are held against lateral movement.

3. A typewriter construction comprising a channelshaped main frame having a base portion and oppositely disposed upright flange portions, a plurality of key levers for said typewriter, said levers having keys arranged in banks, a pivotal support for the levers of each bank comprising a rod extending between and supported by .said frame flange portions, said rods being in spaced parallel relation, and a cover for said main frame having side portions in overlying relation with said flange portions,

whereby said rods are held against longitudinal movement. 4. The combination according to claim 3, each of said key; levers being of flat shape and having a pivot extension and an actuating arm extending rearwardly of said pivot extension and adapted to be connected to a -type bar, the levers for each bank of keys being of substantially identical outline.-

-' 5. In a typewriter construction, a main frame, a plurality of key levers, pivot rods held by said frame for pivotally .supporting said key levers, a cover for said typewriter, said cover having-a plurality of slots in spaced parallel relationfor guiding the forward portionsof said key levers, and a guide plate adjacent the rear ends of saidkey levers, said guide plate having a plurality .of

slots for guidingthe rearportions of said key levers,

whereby substantial lateral motion of said key levers is prevented. i

6.. A typewriter construction comprising a plurality of key levers, saidkeylevers having actuating arms movable between a rest position and a striking position, said arms when in their rest position being in substantially parallel spaced relation, and a universal bar adjacent said actuating 'arms,-the cdgeof said universal bar facing said 'aactuating arms having a convex shapepwhereby the key lever; actuating arms toward the side extremities of the typewriter have-a longer distance of travel'before engagq ing the universal bar than the arms at the central portion of the typewriter.

7. A typewriter construction comprising a plurality of key levers, said key levers having keys arranged in banks, actuating arms on said key levers movable between a rest position and a striking position, a universal bar above said actuating arms and engageable thereby when one of said arms is moved toward its striking position, the lower edge of said universal bar being convexly shaped so that the actuating arms of the key levers at the extremities of the typewriter are spaced from the universal bar when in their position of rest, and a plurality of recesses in said lower edge, said recesses being aligned with the actuating arms of the key levers bearing the forward bank of keys.

8. In combination according to claim 7, further provided with a plurality of pivot rods for supporting said key levers, and resilient means engaging said universal bar for urging it against said actuating arms, said resilient means being supported by one'of said pivot rods.

9. A typewriter construction comprising a plurality of key levers, a plurality of type bars actuated by said levers, a hanger for said type bars comprising a pair of plates secured in spaced parallel relation,.and guide slots in each of said plates, said guide slots being aligned, the type bars each having a guide portion disposed within a pair of said slots, whereby said type bars are held against substantial lateral movement during their stroke.

10. A typewriter construction comprising a plurality of key levers, a plurality of type bars actuated by said key levers, said type bars each having a shank portion and a guide portion of fiat shape, a hanger for said type bars comprising a pairof plates in spaced parallel relation, and a plurality of guide slots in each of said plates, said guide slots being aligned in pairs, each pair of guide slots being adapted to receive the guide portion of a type bar therein, whereby said guide portion will rotate within said guide slots during the operative movement of said type bars. I

p 11. A typewriter construction comprising a plurality of type bars, said type bars each having a shank portion and a guide portion of flat shape, a hanger for supporting said type bars comprising a pair of plates in spaced parallel relation, an arcuate pivot wire secured to one of said plates at its opposite ends, said wire passing through the guide portions of said type bars, and a plurality of slots in each of said plates, said slots being aligned in pairs, the guide portions of said type bars rotating within said slots during operative movement of the type bars.

12. A typewriter construction comprising a plurality of key levers having actuating arms in spaced parallel relation, a plurality of type bars actuated by said key levers, a hanger for said type bars, said hanger comprising a pair of plates in spaced parallel relation, type bar guide slots in said plates for governing the operative movement of said type bars, and a plurality of key lever guide slots in the lower portion of one-of said plates, said key lever actuating arms being disposed within said slots. 1

13. A typewriter construction comprising a plurality of type bars each having a shank portion and a guide portion of flat shape, a hanger for said type bars comprising a .pairof vertically disposed plates secured together in spaced parallel relation, a plurality of guide slots in each of said plates, the guide portions of said type bars being movable within said guide slots, and means for aligning said plates so as to preadjust the relative positions of said guide slots,

said aligning means comprising a portion on each plate for] said typewriter comprising a pair of carriage frame side sections disposed outwardly of said hanger and pivot- ,ally secured to said main frame side portions.

15. A typewriter construction comprising a main frame having a flat base portion and upright side portions, la plurality of. key levers, pivot rods for said key leyers extending between said side portions, a universal bar adjacent said key levers, saiduniversal bar comprising a bar having a main web portion and oppositely disposed legs, a pair of rocking posts extending upwardly from said legs, said rocking posts being pivotally supported by one of said pivot rods, a ribbon spool mechanism, a linkJextending from one of said rocking posts for actuating said ribbon spool mechanism, a carriage escapement mechanism, and an actuating bar connected to said rocking posts for actuating said escapement mechanism.

16. The combination according to claim 15, said actuating bar comprising a rod having an actuating portion engaging said escapement mechanism and oppositely disposed connecting portions extending between said actuating portion and said rocking posts.

17. In a typewriter construction, a main frame having oppositely disposed upright side portions, a carriage adapted to support a platen, a frame for said carriage comprising a pair of oppositely disposed side plates in substantially the same plane as said main frame side portions, and a pair of pivot posts extending upwardly from said side portions, said carriage frame side plates being pivotally secured to said posts, whereby the upper edges of said main frame side portions are in. supporting engagement with the lower edges of said carriage frame side plates.

18. A typewriter construction comprising a main frame having oppositely disposed side portions, a carriage frame pivotally supported by said main frame and comprising a pair of oppositely disposed side plates, a carriage rail extending between said side plates and secured thereto, said side plates being in substantially the same plane as. said main frame side portions and swingable into abutting relation therewith, and a pair of ribbon spool mechanisms, said ribbon spool mechanisms being secured to and movable with said carriage side plates.

19. A typewriter construction comprising a main frame having upright side portions, a carriage frame pivotally secured to said side portions, said carriage frame comprising side plates having a pivotal connection with said upright side portions and a carriage rail extending between said side plates, an escapement mechanism secured to the rear of said carriage rail, a carriage movably mounted on said carriage rail, and a rack on said carriage and engageable by said escapement mechanism.

20. In combination with a typewriter construction comprising a main frame and a carriage frame movably supported by said main frame, a carriage mounted on said carriage frame, said carriage comprising a unitary plate having laterally bent cars at its opposite ends, said ears being adapted to support a platen therebetween, and a downwardly bent flange portion along the rear edge of said plate, said flange portion having a plurality of rack teeth formed at its lower edge for cooperaion with an escapement mechanism.

21. The combination. according to claim 20, said plate beingfurther provided with a pair of oppositely disposed ball bearing race portions, saidportions comprising longitudinal troughs formed from said plate.

22. A typewriter construction comprising a main frame, a carriage framemovably supported by said main frame and including a pair of side plates and a carriage rail secured therebetween, said carriage railcomprising an elongated plate having laterally extending flanges, a pair of .ball bearing races formed as .troughs on said flanges,

a'carriage movably mounted onsaid carriage rail, said.

carriage comprising a plate having a pair of upstanding ears adapted to support a platen therebetween, a pair of flanges along the opposite edges of said carriage plate, saidflanges having troughs formed thereimwhereby antifriction bearings may be retained between said carriage rail and said carriage, and an escapement rack formed on one of said carriage plate flanges outwardly of i said trough.

23. A typewriter construction comprising a main frame, a carriage frame movablysupported on said. mainframe a carriage movablymounted on said carriage frame, a platen rotatably supported by said carriage, a feed roller adjacent said platen and movable between a gripping position and=a releasing position; and a feed roller supporting member for holding said feed roller, said feed roller supporting member comprising a plate of arcuate shape pivotally supported at its forward end by said carriage; andresilientmeans engageable with a portion 18 of said feed roller supporting member for urging the feed roller into its gripping position.

24. The combination according to claim 23, said feed roller supporting member partially surrounding said platen, the rear edge of said memberbeing accessible to the operator, whereby manual depression of said rear edge will move the feed roller to its releasing position against the action of said resilient means.

25. A typewriter construction comprising a main frame, a carriage frame pivotally supported on said main frame, a carriage movably mounted on said carriage frame, a ribbon guide member mounted on said carriage frame and movable therewith, and a type bar guide member secured to said main frame adjacent said ribbon guide member, said typebar guide member and ribbon guide member being normally in overlying parallel relation, whereby pivotal movement of said carriage frame will change the angular position of said ribbon guide member relative to said type bar guide member.

26. The combination according to claim 25, further provided with supporting means for said ribbon guide member, said supporting means comprising a guide bracket supported by said carriage frame, said ribbon guide member being movable on said guide bracket between a retracted and an extended position.

27. In a typewriter construction, a plurality of key levers, a universal bar movable by said key levers between a rest position and a striking position, an escapement mechanism actuated by said universal bar, said escapement mechanism comprising a pawl and leaf spring mounted for reciprocating movement, and a carriage having a rack controlled by said pawl and leaf spring, said rack being engageable with and held stationary by said pawl when the universal bar is moved from its rest position to its striking position, said rack being further engageable with and permitted spacing movement by said leaf spring when the universal bar is returned to its rest position.

28. In a typewriter construction, a universal bar movable between a rest position and an actuatingposition, acarriage having a rack thereon, an ascapement mecha-' nism actuatable by movement of said universal bar, said escapement mechanism comprising a pawl pivotally mounted adjacent said rack and movable between a lock ing position and a holding position, the pawl being in non-obstructing relation with said rack when in its locking position and in obstructing relation therewith when in its holding position, a spring leaf movable with said pawl, said sprng leaf being in obstructing relation with said rack when said pawl is in its locking position, and

a floating support for said escapement mechanism con? tinually urged in the direction of said rack.

A typewriter construction comprising a carriage having a rack thereon, an escapement mechanism com-- prising a pawl pivotally mounted adjacent said rack and movable between a locking position and a holding position, said pawl having a recess in alignment with said rack when the pawl is in its locking position, a spring leaf movable with said pawl, said spring leaf having a portion overlapping said recess, whereby the spring leaf will prevent movement of said rack when the pawl is in' its locking position, said spring leaf being movable parallel to said rack when the pawl is moved to its holding position, and means for limiting the spring leaf movement to substantially one tooth pitch, whereby said spring leaf will be moved into obstructing relation with the next succeeding tooth on said rack when the pawl is moved back to locking position.

anism comprisinga pair of pawls alternately engageable with said rack, means for pivotally supporting said pawls comprising a cage having a pivot pin, both of said pawls being mounted for simultaneous pivotal movement on said pivot pin independently of movement of said cage, and

meansfor resiliently mounting said cage adjacent said car riage for bodily movement about a pivot axis spaced from said first pivot, whereby the cage may be manually moved into a retracted position wherein said pawls are both" moved outof engagement with said rack.

31. A typewriter construction comprising a, carriage having a rack thereon, an escapement mechanism for: controlling the movement of said rack, sa'id'escapement aromas mechanism comprising a pawl pivotally mounted adjacent said rack and movable between a position out of obstructing engagement with the rack and a position in engagement therewith, an actuating bar for moving said pawl between its said positions, a recess in said pawl for receiving the actuating bar therethrough, and resilient means for urging said actuating bar into said recess.

32. The combination according to claim 31, further provided with a ribbon guide movably mounted adjacent said carriage, and an actuating lever for said ribbon guide, said resilient means being engageable with said actuating lever, whereby movement of said actuating bar will cause simultaneous movement of said escapement mechanism and said ribbon guide.

33. The combination according to claim 31, further provided with movable supporting means for said escapement mechanism, mounting means for said movable supporting means, and a ribbon guide movably mounted adjacent said carriage, said escapement mounting means beirdig integral with the mounting means for said ribbon gut e.

34. A typewriter construction comprising a main frame, a carriage frame movably supported by said main frame, a carriage slidably mounted on said carriage frame, said carriage comprising a plate having upstanding ears at the opposite ends thereof, a platen rotatably supported between said ears, a circular feeding ratchet at one end of said platen, said ratchet having teeth extending parallel to the axis of said platen, a retaining pawl for said ratchet comprising a projection on one of said ears, and a spring at the opposite end of said platen and held between the other of said ears and the platen for urging said ratchet into engagement with said pawl.

35. A typewriter construction comprising a main frame, a carriage frame movably mounted thereon, a pair of oppositely disposed ribbon spool supporting brackets secured to said carriage frame; and a ribbon spool mechanism supported by each of said brackets, said mechanism comprising a vertically disposed spool shaft, a ratchet at the lower end of said shaft for intermittently rotating the shaft, a spool mounting portion at the upper end of said shaft, and a clutch mechanism for releasably holding the spool for rotary movement with the shaft, said clutch mechanism being movable between releasing and holding positions.

'36. In a typewriter construction, a carriage frame, a pair of oppositely disposed ribbon spool mounting brackets on said carriage frame; and a ribbon spool mechanism supported by each of said brackets, said mechanism comprising a shaft rotatably supported by the leg portions of said bracket, an intermittent actuating means for said shaft, a spool supporting portion on said shaft, and a spool gripping mechanism on said shaft for releasably holding the spool for rotation with the shaft, said spool gripping mechanism being movable between releasing and holding positions.

37. In a typewriter construction, a ribbon spool mechanism comprising a spool shaft, a ratchet on said shaft, a pawl engageable with said ratchet for intermittently rotating the shaft, a spool supporting portion on said shaft, and a clutch mechanism for releasably holding the spool for rotation with the shaft, said clutch mechanism comprising a snap type leaf spring adjacent the spool and movable between a gripping position in engagement with the spool and a releasing position away from the spool.

38. In a typewriter construction, a ribbon spool mechanism comprising a spool shaft, a ratchet secured to said shaft, a pawl supporting plate rockable around said shaft, a pawl pivotally supported by said plate and having a tooth portion engageable with said ratchet, and a universal bar linked to said pawl and movable between a rest position and an actuating position, said universal bar when moved toward its actuating position causing said pawl to be retracted from said ratchet and said plate to be rocked in one direction, movement of said universal bar back toward its rest position causing engagement of said pawl with a succeeding tooth on said ratchet and rocking of said plate in the opposite direction. 7

' 39. In a typewriter construction, a main frame, a carriage frame movably suported thereon between a lower and an upper shift position, a pivotally and slidably mounted shift key lever for moving the carriage from its lower to its upper shift position, and means for locking said carriage in its upper shift position, said means com- '20 prising a member having a locking surface thereon, said shift key lever being slidable into a position in engagement with said locking surface when the lever is held in its upper shift position.

40. In a typewriter mechanism, a main frame, a carriage frame movably supported thereon, said carriage frame being movable between upper and lower shift positions, a shift kev lever slidably and pivotally supported by said main frame, said shift key lever being adapted to lift said carriage frame into its upper shift position, and a locking bracket on said main frame and having a locking surface, said lever having an end portion movable into engagement with said locking surface by sliding movement of the lever When the lever is in its upper shift position.

41. In a typewriter construction, a main frame, a carriage frame movably supported on said main frame and movable between a lower, an intermediate, and an upper shift position, an intermediate shift key lever for moving the carriage frame to its intermediate shift position, an

, upper shift key lever for moving the carriage frame to its upper shift position, and a stop surface for limiting the movement of said intermediate and upper shift key levers, the surface of said intermediate shift key lever opposite said stop surface being closer to the stop surface than the corresponding surface of said upper shift key lever, whereby the intermediate shift key lever is permitted less movement than the upper shift key lever before engaging the stop surface.

42. In a typewritter construction, a main frame, a carriage frame movably supported thereon, said carriage frame being movable into an intermediate shift position and an upper shift position, an intermediate slidable shift key lever for moving the carriage to its intermediate shift position, an upper slidable shift key lever for moving the carriage to its upper shift position, said levers being in adjacent parallel relation, and shift locking means for holding said carriage in either its intermediate or upper shift position, said locking means comprising a locking surface adjacent said levers, the levers each having portions engageable with said locking surface by sliding movement of the levers.

43. The combination according to claim 42, further provided with means for limiting said intermediate shift key lever to relatively less movement than said upper shift key lever before its alignment with said locking surface.

44. In a typewriter construction, a main frame, a carriage frame movably supported thereon, said carriage frame being movable between lower and upper shift positions, a shift key lever for moving the carriage from its lower to its upper shift position, a pair of links connected to opposite sides of said carriage frame, and a torsion bar pivotally supported by said main frame and connecting said links, said torsion bar having a portion engageable by said shift key lever to actuate said carriage frame.

45. In a typewriter construction, a main frame, a carriage framemovably supported thereon, said carriage frame being movable between lower and upper shift positions, a shift key lever for actuating the carriage frame, and a combined stopping and locking means for said shift key lever, said means comprising a bracket extending upwardly from said main frame, a laterally extending stop flange at'the upper end of said bracket and in obstructing relation with a portion of said shift key lever, and a locking surface below said stop flange, said shift key lever being slidable into engagement with said locking surface after its engagement with said step flange.

46. In a typewriter construction, a main frame, a car- 1 riage frame movably'supported thereon, a plurality of key levers, pivot rods mounted on said main frame for pivotally supporting said key levers, a shift key lever for moving said carriage between lower and upper shift positions,

' tween said carriage and rail, a cage for guiding saidantifriction bearings, said cage being disposed between said carriage and rail, and a plurality of laterally extending stops on said carriage and rail, said stops being disposed in the pathpf movement of said cage and simultaneously engageable with the cage, whereby further movement of 852,721 Howell May 7, 1907 said carriage on said rail will be prevented. 884,347 Yetman Apr. 7, 1908 1,029,324 Sholes June 11, 1912 References Cited in the file of this patent 5 1,125,139? griggs JJuly g3,

,1 etermann une UNITED STATES PATENTS 1,249,022 Burridge Dec. 4, 1917 442,697 Williams Dec. 16, 1890 1,254,501 Henry Jan. 22, 1918 819,353 Latta May 1, 1906 2,155,777 Steffen Apr. 25, 1939 851,988 Howell Apr. 30, 1907 2,532,802 Farwell Dec. 5, 1950 

